The present invention concerns a novel process for bonding leather to leather without the use of any adhesives. The bonding of leather to leather is achieved in accordance with the present invention by the application of heat and high pressures and the process may thus be compared to welding.
The hitherto known methods of securing pieces of leather to each other include stitching, stapling, rivetting and the like and in particular glueing (e.g. with animal glue, contact cement, polyurethane adhesives, etc.). Each of these methods has its drawbacks as regards the strength and the durability of the connection or bond between the leather pieces, the aesthetic appearance of the product and, in some cases, the complexity of the operational procedure and its adaptability to large-scale manufacture and/or automation. Thus, for example, a glueing operation of leather, say in the shoe industry, involves quite a number of individual operational steps including the preliminary preparation of the leather surfaces for the glueing, application of the adhesive, pressing, drying and subsequent finishing.
It has surprisingly been found in accordance with the present invention that a very strong and permanent bond between two portions of leather can be effected by the application of heat and high pressure to the bonding zone for a comparatively short duration without the need of any auxiliary bonding materials or devices such as adhesives, yarn or metallic or nonmetallic staples, rivets or the like.